More than 500 miles above the Arctic Circle and at 10,551 ft. (3,216 meters) above sea level, it rained for the first time. On August 14, 2021, temperatures at Summit Station – a research station at the highest point on the Greenland Ice Sheet – rose to slightly above freezing, allowing rain to fall. There is no record of rain at the station since observations began in the 1980s – and computer simulations show no evidence for rain going back even further. Above-freezing temperatures at Summit are rare – before this century, ice cores (tubes of ice collected from depth within a mass of ice) showed they had occurred only six times in the past 2,000 years. The years 2012, 2019 and now 2021 have all seen above-freezing temperatures at Summit. Back in 2012 and 2019, warm air temperatures alone, not rain, caused previous major melt events at Summit Station (these are defined as brief periods with more melting and runoff than during typical summer days). Studies have now shown that the amount of melting across Greenland caused by rain has increased over the recent past (https://tc.copernicus.org/articles/13/815/2019/).
Getting rain in this region requires a lot of warm, moist air to be pushed up from lower latitudes. That is happening more frequently with climate change. More specifically in this case, a strong low-pressure center over Baffin Island and high pressure southeast of Greenland conspired to push warm air and moisture rapidly from the south. The recent rain at Summit was accompanied by a massive ice melt event of 872,000 square kilometers. Only one other year – 2012 – had multiple melt events over 800,000 square kilometers. This is the latest in the year it has ever occurred – leading to a surface mass loss seven times higher than the mid-August average. By the time it’s the middle of August, usually there’s a rapid decline in temperature, causing melting to slow down.
Melting ice sheets in Greenland and Antarctica are expected to be the main contributors to sea level rise – an impact of climate change that will lead to dangerous and costly coastal flooding worldwide. The fact that it rained at the highest point on the Greenland Ice Sheet – where the ice is 2 miles thick – is another warning from the planet. It’s in our best interest to listen – and do something about it. In one way or another, climate change will end up impacting ALL of us.
Photo by Dr. Ulyana Horodyskyj while visiting Kulusuk, Greenland in 2008.